CN115050864A - Preparation method of single crystal nitride Micro-LED array based on non-single crystal substrate - Google Patents

Abstract

The invention discloses a preparation method of a single crystal nitride Micro-LED array based on a non-single crystal substrate. The present invention obtains a dislocation filter layer with a dislocation density lower than 1×10 ⁹ cm ^-2 by preparing a two-dimensional material mask layer, and further obtains a single crystal nitride with a dislocation density lower than 1×10 ⁸ cm ^-2 The thin film can realize ultra-high-quality single-crystal nitride functional structures on non-single-crystal substrates with large lattice mismatch and large thermal expansion coefficient mismatch. In addition to being used to fabricate Micro-LED devices, it can also be extended to fabricate Radio frequency devices, power devices, light-emitting devices and detection devices, etc., have process universality; the use of laser to destroy the interface between the epitaxial structure and the non-single crystal substrate can realize the non-destructive separation of the epitaxial structure and the multiple times of the non-single crystal substrate. Reusable, energy saving, environmental protection, simple process and suitable for mass production.

Description

Fabrication of a single-crystal nitride Micro-LED array based on a non-single-crystal substrate method

technical field

The invention relates to a preparation technology of a semiconductor light-emitting device, in particular to a preparation method of a single crystal nitride Micro-LED array based on a non-single crystal substrate.

Background technique

Due to the scarcity of homogeneous substrates, nitride semiconductors are usually heteroepitaxially grown on single crystal substrates with matching lattice symmetry. For example, a single crystal sapphire substrate with high transmittance is usually selected for the preparation of nitride light-emitting devices, and a single crystal silicon or single crystal silicon carbide substrate is usually selected for the preparation of electronic devices. However, the above single-crystal substrates cannot fully meet the requirements of light-emitting devices in terms of light extraction efficiency, transparency, and heat dissipation capability. performance, reduce cost, and expand device application areas.

Single-crystal nitride films can be realized on non-single-crystal substrates such as quartz by assisted epitaxy of single-crystal two-dimensional materials, but there are the following problems: (1) When the thickness of the epitaxial film exceeds 1 μm, the epitaxial film will not The interface interaction of the 2D material will be stronger than the interface interaction between the 2D material and the non-single crystal substrate, resulting in the breakage of the epitaxial film due to partial interface separation during growth or cooling; (2) When the thickness of the epitaxial film is less than 1 μm, The dislocation density of epitaxial thin films is usually higher than 3×10 ¹⁰ cm ^-2 , and the rocking curve half-width of the corresponding X-ray diffraction (0002) crystal plane is greater than 1 degree, resulting in low electro-optical conversion efficiency of light-emitting devices fabricated thereon and electronic devices. The leakage is serious and cannot meet the application requirements of flexible LEDs, UV LEDs, radio frequency power devices and other fields, especially the research and development requirements in the field of Micro-LEDs with extremely high material quality requirements.

SUMMARY OF THE INVENTION

In order to overcome the above deficiencies of the prior art, the present invention proposes a method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate.

The method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate of the present invention includes the following steps:

1) Prepare the template layer:

a) Provide non-single crystal substrates, which are made of rigid non-metallic materials; perform double-sided polishing on non-single crystal substrates;

b) A two-dimensional atomic crystal induced layer is formed on the upper surface of the non-single crystal substrate by wet or dry transfer. The two-dimensional atomic crystal induced layer is a single crystal structure with doped atoms and is exposed to the two-dimensional atomic crystal. Doping atoms on the surface of the induction layer provide surface unsaturated dangling bonds, which serve as nucleation sites for single-crystal nitrides and provide the desired modified surface for single-crystal nitride growth;

c) depositing the first layer of single crystal nitride on the two-dimensional atomic crystal induction layer to form a template layer;

2) Prepare the dislocation filter layer:

a) transferring the first two-dimensional material mask layer to the upper surface of the template layer;

b) By the method of mask protection and selective etching, a first through hole array composed of a plurality of periodic two-dimensionally arranged through holes is formed on the first two-dimensional material mask layer, and the period of the row and column is equal , the depth of each through hole is consistent with the thickness of the first two-dimensional material mask layer, and the diameter of the through hole is less than 2/3 of the period of the first through hole array;

c) A second layer of single crystal nitride is deposited on the first two-dimensional material mask layer, and the surface other than the first through hole array on the first two-dimensional material mask layer does not have surface unsaturated dangling bonds and cannot grow single crystals Nitride, the region of the template layer corresponding to the first through-hole array, has surface unsaturated dangling bonds and can grow single-crystal nitride to realize the first dislocation filtering, that is, the template layer not corresponding to the first through-hole array. Dislocations cannot enter into the second layer of single crystal nitride in the upper layer;

d) Increasing the growth temperature and the stoichiometric ratio of nitrogen source and group III source flow rate, after the thickness of the second layer of single-crystal nitride exceeds the thickness of the first two-dimensional material mask layer, continues to grow vertically while expanding laterally, Until the first two-dimensional material mask layer is completely wrapped, the lateral expansion process is in a nearly stress-free state, resulting in the expansion of dislocations from the region of the template layer corresponding to the first through-hole array to the second layer of single-crystal nitride. The propagation direction is changed, so that some dislocations are annihilated, and a dislocation filter layer with a dislocation density lower than that of the template layer is obtained;

3) Preparation of single crystal nitride films:

a) transferring the second two-dimensional material mask layer to the upper surface of the dislocation filter layer;

b) By the method of mask protection and selective etching, a second through hole array composed of a plurality of periodically two-dimensionally arranged through holes is formed on the second two-dimensional material mask layer, and the depth of each through hole is Consistent with the thickness of the second two-dimensional material mask layer, the period and shape of the second through-hole array are consistent with the first through-hole array, but the position of the second through-hole array has a horizontal offset from the first through-hole array. moving so that the outer edge of the through hole of the second through hole array is tangent to the outer edge of the through hole of the first through hole array;

c) A third layer of single crystal nitride is deposited on the second two-dimensional material mask layer, and the surface outside the second through hole array area on the second two-dimensional material mask layer does not have surface unsaturated dangling bonds and cannot grow single crystals For crystalline nitride, the region of the dislocation filter layer corresponding to the second through hole array can grow single crystal nitride to realize the second dislocation filter, that is, the dislocation in the dislocation filter layer not corresponding to the second through hole array Can not enter the third layer of single crystal nitride in the upper layer;

d) Increasing the growth temperature and the stoichiometric ratio of nitrogen source and group III source flow rate, after the thickness of the third layer of single-crystal nitride exceeds the thickness of the second two-dimensional material mask layer, continues to grow vertically while expanding laterally, Until the second two-dimensional material mask layer is completely wrapped, the lateral expansion process is in a near stress-free state, causing dislocations to expand from the region of the dislocation filter layer corresponding to the second through hole array to the third layer of single crystal nitride, the dislocation The propagation direction of dislocations is changed, so that some dislocations are annihilated, and a single-crystal nitride film with a dislocation density lower than the dislocation filter layer is obtained;

4) Preparation of single crystal nitride Micro-LED array:

a) Transfer the third 2D material mask layer to the upper surface of the single crystal nitride thin film;

b) Through the method of mask protection and selective etching, a third through hole array composed of a plurality of periodic two-dimensionally arranged through holes is formed on the third two-dimensional material mask layer, and the periods of the rows and columns are equal , the depth of each through hole is consistent with the thickness of the third two-dimensional material mask layer, the diameter of the through hole is 1/2 to 3/4 of the third through hole array period, and the third through hole array period is the same as that of the first through hole array. The hole array period is consistent;

c) A single crystal nitride functional structure is deposited on the third two-dimensional material mask layer, and the surface outside the third through hole array area on the third two-dimensional material mask layer does not have surface unsaturated dangling bonds and cannot grow single crystals Nitride functional structure, the area of the corresponding single crystal nitride film under the third through hole array can grow a single crystal nitride functional structure, and the single crystal nitride functional structure is one of ultraviolet or visible light emitting diode structures; controlled deposition The growth temperature and the stoichiometric ratio of nitrogen source and group III source flow during the process make the lateral dimension of the single-crystal nitride functional structure equal to the lateral dimension of the circular via region, and only vertical growth is performed, and the single-crystal nitride functional structure is The height is greater than the thickness of the third two-dimensional material mask layer, forming a single-crystal nitride Micro-LED array with the same periodic distribution as the third through-hole array, and the single-crystal nitride functional structure in each through-hole acts as a single-crystal nitrogen An array element of a Micro-LED array;

5) Obtain a flexible single crystal nitride Micro-LED array:

a) The gaps between the array elements are filled by spin coating, and the filling height is the same as the height of the array elements to obtain a flat sheet structure;

b) Attach a flexible protective layer to the surface of the flat sheet structure;

c) The laser is incident from the back of the non-single crystal substrate, and the laser heats the two-dimensional atomic crystal induced layer between the non-single crystal substrate and the template layer by means of lattice resonance absorption, and melts the two-dimensional atomic crystal induced layer to realize non-single crystal. The single crystal substrate is separated from the structure above the 2D atomic crystal induced layer, resulting in a flexible single crystal nitride Micro-LED array and a reusable non-single crystal substrate.

Wherein, in a) of step 1), the forbidden band width of the non-single crystal substrate is greater than 5 eV, the lattice mismatch with the nitride semiconductor is greater than 20%, the thermal expansion coefficient mismatch is greater than 50%, the visible light transparency is greater than 0.99, and the melting point is greater than 0.99. Above 1200℃, use one of quartz, mica, corundum and diamond.

In b) of step 1), the two-dimensional atomic crystal induction layer adopts graphene with a single crystal structure of doping atoms, the doping atoms are nitrogen atoms or oxygen atoms, and the proportion of nitrogen atoms or oxygen atoms is greater than 1%, With thicknesses ranging from 1 to 10 nm, the doping atoms provide surface unsaturated dangling bonds as nucleation sites for nitrides, and do not require additional modification treatments for the 2D atomic crystal-induced layer.

In c) of step 1), the first layer of single crystal nitride is grown by metal organic chemical vapor deposition technology, molecular beam epitaxy, hydride vapor phase epitaxy, magnetron sputtering or pulsed laser deposition technology, and the growth temperature is 900 °C ~ 1250 ℃, the stoichiometric ratio of the flow rate of nitrogen source and group III source, namely group V/group III, is 300~1000, group III source is metal or metal-organic source, nitrogen source is ammonia or nitrogen, the first layer of single crystal nitrogen The compound is AlN or AlGaN and AlN composite structure, the forbidden band width is greater than 5eV, the thickness of the template layer is 500 nm~1000 nm, and the dislocation density of the template layer is lower than 5×10 ¹⁰ cm ^-2 and higher than 1×10 ⁹ cm ^-2 .

In a) of step 2), the first two-dimensional material mask layer adopts polycrystalline or amorphous structure graphene, boron nitride or transition metal chalcogenide, and has a thickness of 10 nm to 30 nm.

In b) of step 2), the specific process of mask protection and selective etching is as follows: spin-coating photoresist on the upper surface of the mask layer of the first two-dimensional material, pass through the mask with a set periodic shape The photoresist is treated by stencil exposure, and the photoresist denatured by exposure is removed by chemical etching, and the mask protection is provided by the undenatured photoresist with a set periodic shape; selective etching uses plasma etching. The first two-dimensional material mask layer with mask protection is directly etched by techniques such as etching or reactive ion etching. The non-mask protection area is etched, and the mask protection area is not etched, and chemical cleaning is used to remove it. The remaining photoresist layer is transferred from the photoresist layer to the first two-dimensional material mask layer with a set periodic shape. The shape of the through hole is a cylinder; the period of the first through hole array is 0.1 μm~50 μm.

In c) of step 2), the second layer of single crystal nitride is grown by metal organic chemical vapor deposition technology, molecular beam epitaxy, hydride vapor phase epitaxy, magnetron sputtering or pulsed laser deposition technology, and the growth temperature is 900 °C~ At 1250 ℃, the stoichiometric ratio of the flow rate of nitrogen source and group III source, namely group V/group III, is 300~1000, the second layer of single crystal nitride is AlN or AlGaN and AlN composite structure, and the forbidden band width is greater than 5 eV.

In d) of step 2), the growth temperature is increased to 1000 °C to 1350 °C, and the group V/group III ratio is increased to 1500 to 5000. The thickness of the dislocation filter layer is 500 nm~2000 nm, and the dislocation density is lower than 1×10 ⁹ cm ^-2 .

In a) of step 3), the second two-dimensional material mask layer is composed of one of polycrystalline or amorphous structure graphene, boron nitride or transition metal chalcogenide, and the thickness is 10 nm~30 nm.

In c) of step 3), the third layer of single crystal nitride is grown by metal organic chemical vapor deposition technology, molecular beam epitaxy, hydride vapor phase epitaxy, magnetron sputtering or pulsed laser deposition technology, and the growth temperature is 900 ℃~ At 1250 ℃, the stoichiometric ratio of the flow rate of nitrogen source and group III source, namely group V/group III, is 300~1000, the third layer of single crystal nitride is AlN or AlGaN and AlN composite structure, and the forbidden band width is greater than 5 eV.

In d) of step 3), the growth temperature is increased to 1000 °C to 1350 °C, and the group V/group III ratio is increased to 1500 to 5000. The thickness of single crystal nitride films is 500 nm~2000 nm, and the dislocation density is lower than 1×10 ⁸ cm ^-2 .

In a) of step 4), the third two-dimensional material mask layer is composed of one of polycrystalline or amorphous structure graphene, boron nitride or transition metal chalcogenide, and the thickness is 10 nm~30 nm.

In c) of step 4), the growth temperature is 900 ℃~1250 ℃, the stoichiometric ratio of the flow rate of nitrogen source and group III source, that is, group V/group III, is 300~1000; the functional structure of single crystal nitride is the array element It is composed of n-type layer, quantum structure and p-type layer, and the height is 0.5μm~3μm.

In a) of step 5), spin-coat polymethylmethacrylate (PPMA) or polydimethylsiloxane (PDMS).

In b) of step 5), the flexible protective layer is composed of PMMA, transparent conductive film or other flexible organic materials.

In c) of step 5), an infrared laser, ultraviolet laser or visible laser is incident from the back side of the non-single crystal substrate; the wavelength of the infrared laser is greater than 800 nm.

Advantages of the present invention:

The present invention obtains a dislocation filter layer with a dislocation density lower than 1×10 ⁹ cm ^-2 by preparing a two-dimensional material mask layer, and further obtains a single crystal nitride with a dislocation density lower than 1×10 ⁸ cm ^-2 The thin film can realize ultra-high-quality single-crystal nitride functional structures on non-single-crystal substrates with large lattice mismatch and large thermal expansion coefficient mismatch. In addition to being used for the preparation of Micro-LED devices, it can also be expanded to be used in the preparation of Radio frequency devices, power devices, light-emitting devices and detection devices, etc., have process universality; the use of laser to destroy the interface between the epitaxial structure and the non-single crystal substrate can realize the non-destructive separation of the epitaxial structure and the multiple times of the non-single crystal substrate. Reuse, energy saving and environmental protection, simple process and suitable for mass production.

Description of drawings

1 is a cross-sectional view of a template layer obtained by a method for preparing a single-crystal nitride Micro-LED array based on a non-single-crystal substrate of the present invention;

2 is a cross-sectional view of a dislocation filter layer obtained by a method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate of the present invention;

3 is a cross-sectional view of a single crystal nitride thin film obtained by a method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate of the present invention;

4 is a cross-sectional view of preparing a single crystal nitride Micro-LED array according to the method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate of the present invention;

5 is a cross-sectional view of a flexible single-crystal nitride Micro-LED array obtained by the method for preparing a single-crystal nitride Micro-LED array based on a non-single-crystal substrate of the present invention.

Detailed ways

Below in conjunction with the accompanying drawings, the present invention will be further described through specific embodiments.

The method for preparing a single crystal nitride Micro-LED array based on a non-single crystal substrate of this embodiment includes the following steps:

1) Prepare the template layer:

a) Provide a non-single crystal substrate 1, the forbidden band width of the non-single crystal substrate is greater than 5 eV, the lattice mismatch with the nitride semiconductor is greater than 20%, the thermal expansion coefficient mismatch is greater than 50%, the visible light transparency is greater than 0.99, and the melting point is high. Quartz at 1200°C; double-sided polishing of non-single crystal substrates;

b) A two-dimensional atomic crystal induction layer 2 is formed on the upper surface of the non-single crystal substrate by wet or dry transfer. The two-dimensional atomic crystal induction layer is a single crystal structure with nitrogen doping atoms, and the proportion of nitrogen atoms is is 1.2% and has a thickness of 5 nm. The dopant atoms exposed on the surface of the 2D atomic crystal-induced layer provide surface unsaturated dangling bonds, which act as nucleation sites for nitrides and provide the desired modified surface for single-crystal nitride growth. ;

c) Using metal organic chemical vapor deposition technology to deposit single crystal AlN on the two-dimensional atomic crystal induced layer to form the first layer of single crystal nitride to form template layer 3 with a thickness of 800 nm, the dislocation density of the template layer is lower than 5 × 10 ¹⁰ cm ^-2 and higher than 1×10 ⁹ cm ^-2 , as shown in Figure 1;

2) Prepare the dislocation filter layer:

a) Transfer the first two-dimensional material mask layer 4 to the upper surface of the template layer, and the first two-dimensional material mask layer is polycrystalline graphene with a thickness of 15 nm;

b) Spin-coat photoresist on the upper surface of the mask layer of the first two-dimensional material, expose the photoresist through a mask with a set periodic shape, and remove the photoresist denatured by exposure by chemical etching , mask protection is provided by an undenatured photoresist with a set periodic shape; selective etching is to directly etch the first two-dimensional mask with mask protection by techniques such as plasma etching or reactive ion etching. Material mask layer, the non-mask protection area is etched, the mask protection area is not etched, the remaining photoresist layer is removed by chemical cleaning, and the photoresist layer with the set periodic shape is removed from the photoresist layer. Transfer to the first two-dimensional material mask layer, the shape of the through hole is a cylinder; form a first through hole array composed of a plurality of periodically two-dimensionally arranged through holes on the first two-dimensional material mask layer, row Equal to the period of the column, the depth of each through hole is consistent with the thickness of the first two-dimensional material mask layer, the diameter of the through hole is 1/2 of the period of the first through hole array, and the period of the first through hole array is 5 μm;

c) Using metal organic chemical vapor deposition technology to deposit single crystal AlN on the first two-dimensional material mask layer to form a second layer of single crystal nitride, the growth temperature is 1050 ° C, the flow rate of nitrogen source and III source stoichiometric ratio That is, the V group/III group is 500, the forbidden band width of the second layer of single crystal nitride is greater than 5 eV, and the surface other than the first through hole array on the first two-dimensional material mask layer does not have surface unsaturated dangling bonds and cannot For growing single crystal nitride, the area of the template layer corresponding to the first through hole array has surface unsaturated dangling bonds, which can grow single crystal nitride and realize the first dislocation filtering, that is, the template corresponding to the non-first through hole array The dislocations in the layer cannot enter into the second layer of single crystal nitride in the upper layer;

d) The growth temperature increases to 1150 °C, and the V group/III group ratio increases to 2000. After the thickness of the second layer of single crystal nitride exceeds the thickness of the first two-dimensional material mask layer, it continues to grow vertically while expanding laterally. Until the mask layer of the first two-dimensional material is completely wrapped, the near stress-free state of the lateral expansion process results in a change in the propagation direction of dislocations extending from the region of the template layer corresponding to the first through-hole array to the second layer of single-crystal nitride. , so that some dislocations are annihilated, and a dislocation filter layer 5 with a dislocation density lower than 1×10 ⁹ cm ^-2 is obtained, and the thickness of the dislocation filter layer 5 is 1500 nm, as shown in Figure 2;

3) Preparation of single crystal nitride films:

a) Transfer the second two-dimensional material mask layer 6 to the upper surface of the dislocation filter layer, and the second two-dimensional material mask layer is made of polycrystalline graphene with a thickness of 20 nm;

b) By the method of mask protection and selective etching, a second through hole array composed of a plurality of periodically two-dimensionally arranged through holes is formed on the second two-dimensional material mask layer, and the depth of each through hole is Consistent with the thickness of the second 2D material mask layer, the period and shape of the second through hole array are consistent with the first through hole array of the first 2D material mask, but the position of the second through hole array is the same as that of the first through hole array. The array is horizontally offset along the row direction, and the horizontal offset is the diameter of the through hole;

c) Using metal organic chemical vapor deposition technology to deposit single crystal AlN on the second two-dimensional material mask layer to form a third layer of single crystal nitride, the growth temperature is 1050 °C, the flow rate of nitrogen source and group III source stoichiometric ratio That is, the V group/III group is 500, the forbidden band width of the third layer of single crystal nitride is greater than 5 eV, and the surface of the second two-dimensional material mask layer outside the second through hole array area does not have surface unsaturated dangling bonds but Single-crystal nitride cannot be grown, and the area of the dislocation filter layer corresponding to the second through-hole array can grow single-crystal nitride to realize the second dislocation filter, that is, in the dislocation filter layer not corresponding to the second through-hole array The dislocations cannot enter into the upper third layer of single crystal nitride;

d) When the growth temperature is increased to 1150 °C, the V group/III group ratio is increased to 2000, so that the thickness of the third layer of single crystal nitride exceeds the thickness of the second two-dimensional material mask layer, and the vertical growth is continued while lateral expansion, Until the second two-dimensional material mask layer is completely wrapped, the near stress-free state of the lateral expansion process leads to the expansion from the region of the dislocation filter layer corresponding to the second through hole array to the dislocation propagation direction of the third layer of single crystal nitride changes, so that some dislocations are annihilated, and a single crystal nitride film 7 with a dislocation density lower than 1×10 ⁸ cm ^-2 is obtained, and the thickness of the single crystal nitride film 7 is 1500 nm, as shown in Figure 3;

4) Preparation of single crystal nitride Micro-LED array:

a) Transfer the third two-dimensional material mask layer 8 to the upper surface of the single crystal nitride film, and the third two-dimensional material mask layer is made of polycrystalline graphene with a thickness of 20 nm;

b) Through the method of mask protection and selective etching, a third through hole array composed of a plurality of periodic two-dimensionally arranged through holes is formed on the third two-dimensional material mask layer, and the periods of the rows and columns are equal , the depth of each through hole is consistent with the thickness of the third two-dimensional material mask layer, the diameter of the through hole is 3/5 of the third through hole array period, and the third through hole array period is consistent with the first through hole array period;

c) Using metal organic chemical vapor deposition technology, the growth temperature is 1050 °C, the stoichiometric ratio of the flow rate of nitrogen source and group III source, that is, group V/group III, is 500, and the nitride is deposited on the third two-dimensional material mask layer. Functional structure, the surface of the third two-dimensional material mask layer outside the third through hole array area does not have surface unsaturated dangling bonds and cannot grow the nitride functional structure, and the corresponding single crystal nitride thin film under the third through hole array has no surface. The area can grow a nitride functional structure, and the nitride functional structure is one of ultraviolet or visible light emitting diode structures; by controlling the growth temperature in the deposition process, the stoichiometric ratio of the nitrogen source and the flow rate of the III source, the nitride functional structure is made. The lateral dimension of the structure is equal to the lateral dimension of the circular through-hole region, and only the vertical growth is performed to form a single-crystal nitride Micro-LED array 9 with the same periodic distribution as the third through-hole array 9, the nitride function in each through-hole The structure is used as an array element of a single crystal nitride Micro-LED array with a height of 1 μm, as shown in Figure 4;

5) Obtain a flexible single crystal nitride Micro-LED array:

a) The gaps between the array elements are filled by spin-coating polymethyl methacrylate 10, and the filling height is the same as the height of the array elements to obtain a flat sheet structure;

b) A transparent conductive film is attached to the surface of the flat sheet structure as a flexible protective layer 11;

c) Incident infrared laser from the back of the non-single crystal substrate with a wavelength greater than 800 nm, the infrared laser heats the two-dimensional atomic crystal induced layer between the non-single crystal substrate and the template layer by means of lattice resonance absorption, and melts the two-dimensional atomic crystal induced layer. The atomic crystal induction layer realizes the separation of the structure above the non-single crystal substrate and the two-dimensional atomic crystal induction layer to obtain a flexible single crystal nitride Micro-LED array and a reusable non-single crystal substrate, as shown in Figure 5.

Finally, it should be noted that the purpose of publishing the embodiments is to help further understanding of the present invention, but those skilled in the art can understand that various replacements and modifications can be made without departing from the spirit and scope of the present invention and the appended claims. It is possible. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection of the present invention shall be subject to the scope defined by the claims.

Claims (10)

1. A preparation method of a single crystal nitride Micro-LED array based on a non-single crystal substrate is characterized by comprising the following steps:

1) preparing a template layer:

a) providing a non-single crystal substrate, wherein the non-single crystal substrate is made of rigid non-metal materials; carrying out double-sided polishing on the non-single crystal substrate;

b) forming a two-dimensional atomic crystal induction layer on the upper surface of the non-single crystal substrate in a wet or dry transfer mode, wherein the two-dimensional atomic crystal induction layer is of a single crystal structure with doped atoms, and the doped atoms exposed on the surface of the two-dimensional atomic crystal induction layer provide surface unsaturated dangling bonds which serve as nucleation sites of single crystal nitrides and provide a required modified surface for the growth of the single crystal nitrides;

c) depositing a first layer of single crystal nitride on the two-dimensional atomic crystal inducing layer to form a template layer;

2) preparing a dislocation filter layer:

a) transferring the first two-dimensional material mask layer to the upper surface of the template layer;

b) forming a first through hole array consisting of a plurality of through holes periodically arranged in two dimensions on the first two-dimensional material mask layer by a mask protection and selective etching method, wherein the periods of rows and columns are equal, the depth of each through hole is consistent with the thickness of the first two-dimensional material mask layer, and the diameter of each through hole is smaller than 2/3 of the period of the first through hole array;

c) depositing a second layer of single crystal nitride on the first two-dimensional material mask layer, wherein the surface of the first two-dimensional material mask layer, except the first through hole array, is not provided with a surface unsaturated dangling bond and can not grow the single crystal nitride, and the area of the template layer, corresponding to the lower part of the first through hole array, is provided with a surface unsaturated dangling bond and can grow the single crystal nitride, so that first dislocation filtering is realized, namely dislocations in the template layer, which are not corresponding to the first through hole array, can not enter the second layer of single crystal nitride on the upper layer;

d) increasing the growth temperature and the stoichiometric ratio of the flow of the nitrogen source and the III-group source, and after the thickness of the second layer of single crystal nitride exceeds the thickness of the first two-dimensional material mask layer, continuing to grow longitudinally and simultaneously expand transversely until the first two-dimensional material mask layer is completely wrapped, wherein the transverse expansion process is in a near-stress-free state, so that when the dislocations are expanded from the region of the template layer corresponding to the first through hole array to the second layer of single crystal nitride, the propagation direction of the dislocations is changed, part of the dislocations are annihilated, and a dislocation filter layer with the dislocation density lower than that of the template layer is obtained;

3) preparing a single crystal nitride film:

a) transferring the second two-dimensional material mask layer to the upper surface of the dislocation filtering layer;

b) forming a second through hole array consisting of a plurality of through holes which are periodically arranged in a two-dimensional manner on the second two-dimensional material mask layer by a mask protection and selective etching method, wherein the depth of each through hole is consistent with the thickness of the second two-dimensional material mask layer, the period and the shape of the second through hole array are consistent with those of the first through hole array, but the position of the second through hole array and the first through hole array have horizontal offset, and the horizontal offset ensures that the outer edge of each through hole of the second through hole array is tangent to the outer edge of each through hole of the first through hole array;

c) depositing a third layer of single crystal nitride on the second two-dimensional material mask layer, wherein the surface of the second two-dimensional material mask layer, except the second through hole array region, does not have surface unsaturated dangling bonds and can not grow the single crystal nitride, and the region of the corresponding dislocation filter layer below the second through hole array can grow the single crystal nitride, so that second dislocation filtration is realized, namely, dislocations in the dislocation filter layer which is not corresponding to the second through hole array can not enter the third layer of single crystal nitride on the upper layer;

d) increasing the growth temperature and the stoichiometric ratio of the flow of the nitrogen source and the group III source, and after the thickness of the third layer of single crystal nitride exceeds the thickness of the second two-dimensional material mask layer, continuing to grow longitudinally and simultaneously expand transversely until the second two-dimensional material mask layer is completely wrapped, wherein the transverse expansion process is in a near-stress-free state, so that when dislocations are expanded from the region of the dislocation filter layer corresponding to the second through hole array to the third layer of single crystal nitride, the propagation direction of the dislocations is changed, and partial dislocations are annihilated to obtain the single crystal nitride film with the dislocation density lower than that of the dislocation filter layer;

4) preparing a single crystal nitride Micro-LED array:

a) transferring the third two-dimensional material mask layer to the upper surface of the single crystal nitride film;

b) forming a third through hole array consisting of a plurality of through holes which are periodically arranged in a two-dimensional manner on the third two-dimensional material mask layer by a mask protection and selective etching method, wherein the periods of rows and columns are equal, the depth of each through hole is consistent with the thickness of the third two-dimensional material mask layer, the diameter of each through hole is 1/2-3/4 of the period of the third through hole array, and the period of the third through hole array is consistent with the period of the first through hole array;

c) depositing a single crystal nitride functional structure on a third two-dimensional material mask layer, wherein the surface of the third two-dimensional material mask layer, except for a third through hole array region, does not have a surface unsaturated dangling bond and cannot grow the single crystal nitride functional structure, the region of the single crystal nitride film, corresponding to the lower part of the third through hole array, can grow the nitride functional structure in a single crystal manner, and the single crystal nitride functional structure is one of ultraviolet or visible light emitting diode structures; by controlling the growth temperature and the stoichiometric ratio of the nitrogen source to the III-group source flow in the deposition process, the transverse dimension of the single crystal nitride functional structure is equal to the transverse dimension of the circular through hole area, only longitudinal growth is carried out, the height of the single crystal nitride functional structure is greater than the thickness of the third two-dimensional material mask layer, a single crystal nitride Micro-LED array which is the same as the third through hole array and is periodically distributed is formed, and the single crystal nitride functional structure in each through hole is used as an array element of the single crystal nitride Micro-LED array;

5) obtaining a flexible single crystal nitride Micro-LED array:

a) filling gaps among the array elements in a spin coating mode, wherein the filling height is the same as the height of the array elements, and obtaining a flat sheet structure;

b) attaching a flexible protective layer on the surface of the flat sheet structure;

c) laser is incident from the back of the non-single crystal substrate, the laser heats the two-dimensional atomic crystal induction layer between the non-single crystal substrate and the template layer in a lattice resonance absorption mode, the two-dimensional atomic crystal induction layer is melted, the structural separation of the non-single crystal substrate and the two-dimensional atomic crystal induction layer is realized, and the flexible single crystal nitride Micro-LED array and the reusable non-single crystal substrate are obtained.

2. The method of manufacturing according to claim 1, wherein in the step 1) a), the non-single crystal substrate has a forbidden band width of more than 5 eV, a lattice mismatch with the nitride semiconductor of more than 20%, a coefficient of thermal expansion mismatch of more than 50%, a visible light transparency of more than 0.99, and a melting point of more than 1200 ℃.

3. The method according to claim 1, wherein in step 1) b), the two-dimensional atomic crystal inducing layer is made of graphene having a single crystal structure with doping atoms, the doping atoms are nitrogen atoms or oxygen atoms, the proportion of the nitrogen atoms or the oxygen atoms is greater than 1%, and the thickness is 1-10 nm.

4. The process of claim 1The method is characterized in that in step 1) c), a first layer of single crystal nitride is grown by adopting a metal organic chemical vapor deposition technology, molecular beam epitaxy, hydride vapor phase epitaxy, magnetron sputtering or pulse laser deposition technology, the growth temperature is 900-1250 ℃, the stoichiometric ratio of the flow of a nitrogen source and a III group source, namely V group/III group, is 300-1000, the III group source is a metal or metal organic source, a nitrogen source is ammonia gas or nitrogen gas, the first layer of single crystal nitride is an AlN or AlGaN and AlN composite structure, the forbidden band width is more than 5 eV, the thickness of a template layer is 500-1000 nm, the dislocation density of the template layer is lower than 5 multiplied by 10 to obtain the dislocation density of the template layer ¹⁰ cm ^-2 And is higher than 1 x 10 ⁹ cm ^-2 。

5. The method of claim 1, wherein in the step 2), the first two-dimensional mask layer is made of graphene, boron nitride or a transition metal chalcogenide with a polycrystalline or amorphous structure and has a thickness of 10 nm to 30 nm.

6. The preparation method according to claim 1, wherein in step 2) c), a metallorganic chemical vapor deposition technique, molecular beam epitaxy, hydride vapor phase epitaxy, magnetron sputtering or pulsed laser deposition technique is used to grow the second layer of single crystal nitride, the growth temperature is 900 ℃ to 1250 ℃, the stoichiometric ratio of the flow rates of the nitrogen source and the group III source, i.e. group V/group III, is 300 to 1000, the second layer of single crystal nitride is AlN or a composite structure of AlGaN and AlN, and the forbidden bandwidth is more than 5 eV.

7. The method of claim 1, wherein in step 2) d), the growth temperature is increased to 1000 ℃ to 1350 ℃, and the group V/group III ratio is increased to 1500 to 5000; the thickness of the dislocation filter layer is 500 nm-2000 nm, and the dislocation density is lower than 1 multiplied by 10 ⁹ cm ^-2 。

8. The method of claim 1, wherein in step 4) c), the growth temperature is 900 ℃ to 1250 ℃, and the stoichiometric ratio of the flow rates of the nitrogen source and the group III source, i.e., group V/group III, is 300 to 1000; the array element consists of an n-type layer, a quantum structure and a p-type layer, and the height of the array element is 0.5-3 mu m.

9. The method of claim 1, wherein in step 5) a) the polymethylmethacrylate or the polydimethylsiloxane is spin-coated.

10. The production method according to claim 1, wherein in c) of step 5), an infrared laser, an ultraviolet laser, or a visible laser is incident from the back surface of the non-single crystal substrate.

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